The background description includes information that may be useful in understanding the present inventive subject matter. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed inventive subject matter, or that any publication specifically or implicitly referenced is prior art.
Transducers (i.e., audio loudspeakers) are well known and generally comprise a radiating surface (e.g., dome, diaphragm, membrane, cone, etc) attached to a voice coil former (also referred to as a bobbin). The voice coil former is attached to a voice coil, which is suspended in a static magnetic field. An amplifier is electrically coupled to the voice coil and provides a current (i.e., signal) to the voice coil. The current produces an electromagnetic field around the coil, which interacts with the static magnetic field and causes the coil to vibrate up and down. The coil, in turn, causes the radiating surface to vibrate, which vibrates the surrounding air to produce audio waves.
One of the problems with transducers is the tendency of the voice coil former to flex and bend as it vibrates up and down. Bending of the voice coil former allows the radiating surface to “wobble” in a sideways motion, which can produce unwanted resonance and sub-optimal sound quality.
US20090214075 to Inoue discloses a loudspeaker having a vibration system comprising (i) a dome diaphragm, (ii) a cone diaphragm, and (iii) a voice coil bobbin. Inoue improves the rigidity of the vibration system by providing a high-strength adhesive bond between the dome diaphragm and the voice coil bobbin.
All materials and references cited herein are incorporated by reference to the same extent as if each individual reference were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
US20100303278 to Sahyoun discloses a low profile speaker that reduces wobble of the voice coil former by using a cone diaphragm that attaches to the former at a point slightly below the top of the former.
Inoue, Sahyoun, and all other known prior art references fail to contemplate that a voice coil former can be reinforced and stiffened by corrugating the top circumferential surface of the former. Furthermore, these references fail to appreciate that a voice coil former can be reinforced and stiffened from the interior side of the former.
Thus, there is still a need for voice coil formers with improved stiffness.